Brown sulfur dye.



MEINHARD HOFFMANN AND GEORG KALISCHER, OF FRANKFORT-ON- THE-MAIN,GERMANY, ASSIGNORS TO LEOPOLD GASSELLA do 00., OF

SAME PLACE.

SULFUR DYE.

SPECIFICATION forming part of Letters Patent No. 660,058, dated October16, 1900.

Application filed June 16, 1900. Serial No. 20,597- (S ecimensJ To (allwhom it may concern.-

Be it known that we, MEINHARD HOFF- MANN and GEORG KALISOHER, citizensof Prussia, and residents of Frankfort-on-the- Main, Hesse-Nassau,Kingdom of Prussia, Germany, have invented certain new and usefulImprovements in Brown Sulfur Dyes and Process of Making Same, of whichthe following is a specification.

If the dinitro oxydiphenylamin obtained from 1. 3. 4 dinitrochlorbenzeneand 1.4 amidophenol is heated with caustic alkalies in an aqueoussolution, it is completely transformed into a brown substance. Theconstitut-ion of this body has not yet been ascertained; but it mustdifier very considerably from the generating material, for whereas thelatter when heated with alkaline sulfids and sulfur yields anintense-black coloring-matter-the known immedial black the transformedproduct when treated in a like manner yields a characteristic browncoloring-matter. The homologous dinitrophenyl oxytolylamin fromdinitrochlorbenacne and amido-o-cresol behaves in a similar way.

Example 1: Forty kilos dinitro oxydiphenylamin dissolved in eighty kiloscausticsoda lye, 40 Baume, and two hundred and forty liters water areboiled for from three to four hours, until no more ammonia is evolved.The solution is then diluted with water and the body formed isprecipitated nol oxytolylamin are boiled together with fifty kiloscaustic-soda lye, 40 Baum, and one hundred and fifty liters water forseveral hours. Then twenty kilos sulfur are introduced and thetemperature raised to 160 centigrade. The dried melt is used directlyfor dyeing.

The dyestuffs thus obtained dissolve easily in water. They areprecipitated by acids and may be again dissolved with caustic al kaliesor sulfid of sodium. They dye cotton an intense brown, especially in awarm bath containing common salt. An after treatment with chromateschanges the shade to ward yellow and increases the fastness.

Having thus described our invention and in what manner the same can beperformed, what we claim as new, and desire to secure by Letters Patent,is-

1. The process of producing brown coloring-matters by heating a dinitrooxydialphylamin of the constitution with caustic alkalies, and meltingthe thus formed compound with sulfur and alkaline sulfids substantiallyas described.

2. The new brown dyestuif derived from dinitro oxydialphylaminhereinbefore de* scribed, which forms a blackish-brown powder easilysoluble in water in presence of caustic alkalies or of alkaline sulfids,being precipitated from its solution by organic or mineral acids, dyeingcotton directly a deep brown fast to washing, to acids and oxidizingagents.

Signed at Frankfort-on-the-Main, in the Province of Hesse-Nassau andKingdom of Prussia, this 26th day of May, A. D. 1900,.

Y MEINHARD HOFFMANN.

GEORG KALISCHER. Witnesses:

RICHARD GUENTHER, JEAN GRUND.

